Appearance of gamma delta T cell receptor-positive cells following alpha beta T cell receptor-positive cells in the lepromin reaction of human skin.

To elucidate the involvement of human gamma delta T cell receptor (TcR)+ cells in mycobacterial infection, we examined the kinetics of these cells in skin lesions of human lepromin reaction. The majority of CD3+ cells two days after induction of the lepromin reaction were alpha beta TcR+, while gamma delta TcR+ cells accounted for only 4.4 +/- 1.4% of the CD3+ cells. On day 21, the incidence of gamma delta TcR+ cells was greater (16.0 +/- 2.1%), although alpha beta TcR+ cells remained the predominant population. These kinetics of alpha beta TcR+ cells and gamma delta TcR+ cells contradict the 'early response, self-surveillance' hypothesis for gamma delta TcR+ cells in mice. Most of the gamma delta TcR+ cells in this study of the lepromin reaction were V delta 1- V delta 2+ V delta 9+, and some of them proliferated in the skin lesions, suggesting that gamma delta TcR+ cells in the lesions may respond to mycobacterial antigens and may play an active part in the lepromin reaction. However, these gamma delta TcR+ cells were not correlated with granuloma formation, the size of necrotic areas, mycobacterial content, or the incidence of CD4+ cells and CD8+ cells.